A pilot effectiveness study: placebo-controlled trial of adjunctive L-triiodothyronine (T3) used to accelerate and potentiate the antidepressant response.

The aim was to evaluate whether adjunctive T3 can help accelerate the antidepressant response and improve overall outcomes when used under naturalistic conditions. Fifty consecutive psychiatric outpatients diagnosed with major depressive disorder who were initiated on antidepressant therapy were randomized to receive adjunctive T3 or placebo in a double-blind manner over the course of 6 wk. There were no restrictions placed on the selection of antidepressant agent, dosing, ancillary medications, or psychotherapy, and there were few exclusion criteria. A positive response was defined as a > or = 50% reduction in Montgomery-Asberg Depression Rating Scale scores. Response rates were higher for the adjunctive T3 cohort compared to the adjunctive placebo cohort after 1 wk (45% vs. 24%) and 2 wk (57% vs. 33%) of treatment. The likelihood of experiencing a positive response at any point over the 6-wk trial was 4.5 times greater in the adjunctive T3 cohort (95% CI 1.3-15.7). The study provides preliminary evidence that T3 can successfully be used in clinical practice to accelerate the antidepressant response and improve overall outcomes. The effectiveness model may be an untapped mechanism for evaluating the value of psychopharmacological agents.